Abstract

A vertically aligned Pd nanowire array was successfully fabricated on an Au/Ti substrate
using an anodic aluminum oxide (AAO) template by a direct voltage electrodeposition
method at room temperature using diluted neutral electrolyte. The fabrication of Pd
nanowires was controlled by analyzing the current–time transient during electrodeposition
using potentiostat. The AAO template and the Pd nanowires were characterized by scanning
electron microscopy (SEM), energy-dispersive X-ray (EDX) methods and X-Ray diffraction
(XRD). It was observed that the Pd nanowire array was standing freely on an Au-coated
Ti substrate after removing the AAO template in a relatively large area of about 5
cm2, approximately 50 nm in diameter and 2.5 μm in length with a high aspect ratio. The
nucleation rate and the number of atoms in the critical nucleus were determined from
the analysis of current transients. Pd nuclei density was calculated as 3.55 × 108 cm−2. Usage of diluted neutral electrolyte enables slower growing of Pd nanowires owing
to increase in the electrodeposition potential and thus obtained Pd nanowires have
higher crystallinity with lower dislocations. In fact, this high crystallinity of
Pd nanowires provides them positive effect for sensor performances especially.